This invention relates to tension devices for sewing machines, and in particular, to those devices utilizing tension discs for providing thread tension.
There are many types of tension devices used to control thread on sewing machines. A large quantity of these devices utilized freely rotatable tension discs which are pressed together by an adjustable spring force, resulting in a controled drag exerted on thread passing therebetween. However, under low tension conditions, with these devices, the thread has a tendency to work its way out of the device.